Last Tuesday, in a strange moment of network television-pop culture syzygy, the new ABC comedy “Selfie” included a scene in which two colleagues, Eliza and Charmonique, were discussing the movie star Renée Zellweger.

The episode, which judging from typical television production schedules had most likely been filmed weeks before, came a day after photographs of a radically different looking Ms. Zellweger flooded news outlets. At Elle magazine’s annual Women in Hollywood celebration last Monday night, Ms. Zellweger’s forehead was as smooth as a packed ski slope, and her eyes as crystal-blue as ever, but they appeared, in some images, wide and round as pennies. In 24 hours, it seemed, every possible news media outlet had a story or a tweet or a blog post decrying the Oscar-winning actress’s new face. Another day passed, and every possible media outlet featured a chat or post or news report defending Ms. Zellweger and her new-looking face. By Friday, we were all ashamed to still be thinking private thoughts about Ms. Zellweger, but we were.

We’ve all seen garish plastic surgery on celebrities. But in the case of Ms. Zellweger, her new appearance set off a battery of intensifying debates. She carved out a career playing accessible characters, wholesome and fallible. In “Dazed and Confused,” as a heartland teenager, and in “Jerry Maguire,” she was winning and approachable. As Bridget Jones, she allowed us to embrace our wine-and-heartache inner insecurities. She made the fat, boozy chain-smokers and job-losers among us feel O.K. about ourselves. She won an Oscar in 2004 for her role in “Cold Mountain,” in which she played a gritty Southern woman working on a failing farm, unafraid to snap a chicken’s neck. Even her personal life offered a dose of reality women could relate to, enjoying a whirlwind love affair and short marriage to the country singer Kenny Chesney in 2005. Who hasn’t had a sloppy breakup?

It’s jarring when suddenly we don’t recognize the person in whom we once saw ourselves.

What is new — and plainly shocking to some — is that Ms. Zellweger now looks like someone not even related to the quirkily pretty, Kewpie-doll star who had us at hello. However the method, she has changed herself into someone who looks like the manicured socialite, the moderately successful commercial actress, the benign political wife. Ms. Zellweger looks beautiful but does not look like Ms. Zellweger.

In another surprising turn, the actress defended herself to People magazine soon after the Elle party, in a statement that attributed her new appearance to healthy living, love and lifestyle changes. “I’m glad folks think I look different!” she said. “I’m living a different, happy, more fulfilling life, and I’m thrilled that perhaps it shows.” As for why she addressed the issue, Ms. Zellweger said, “It seems the folks who come digging around for some nefarious truth which doesn’t exist won’t get off my porch until I answer the door.”

Surgeons are quick to offer their opinions about what has taken place. Dr. Michelle Copeland, a plastic surgeon in New York City, said that Ms. Zellweger had probably elected to have a blepharoplasty, or upper eyelid lift, and possibly also a forehead lift, with the addition of injectable fillers that may have widened the planes of her face. She has also likely benefited from laser or ultrasound procedures that tighten the skin.

The issue is that in all that work, Dr. Copeland said, Ms. Zellweger changed too much. “She was known for having these slightly squinty, slightly hooded eyes,” Dr. Copeland said. “The problem is they totally eliminated that look, and now she is no longer recognizable. She is beautiful, but who is she? Jennifer Grey?” (Dr. Copeland was referring to the “Dirty Dancing” actress whose nose job drastically altered her appearance.)

Nancy Etcoff, an evolutionary psychologist at Harvard and author of “Survival of the Prettiest: The Science of Beauty,” said: “We have gotten used to seeing bad plastic surgery. Two big basketballs on the chest, fish lips, blown-up cheeks. But this is a little different. This is about a lot of subtle changes that add up to a person who no longer looks like our memory of them. She looks like a different person.” Instead of aging along with us, she jumped off the path directly into another identity.

Faces are tightly packed with important biological information, Dr. Etcoff said. “They tell people who we are, who our relatives are, how we feel,” she said. “We are face virtuosos. We can discern one face from thousands, even millions, of other faces. When someone does something to their face that renders them unrecognizable, when that impacts our ability to read their face, it really is a jolt.”

What makes the matter particularly upsetting to any woman over age 39, said Debora L. Spar, the president of Barnard College and the author of “Wonder Women: Sex, Power and the Quest for Perfection,” is that if Ms. Zellweger, an everyday beauty whose work celebrated the flawed and embraced irregularity, apparently succumbed to such dysmorphia, what are the rest of us supposed to do?

“It’s a terrible double bind,” Dr. Spar said, noting the sense of hypocrisy around the situation. “On the one hand, we’re being told don’t worry about how you look, embrace inner goodness and stop judging on external appearance, and yet as a community we have all done nothing but talk about poor Renée Zellweger’s face all week.”

The Zellweger-bashing needs to end, Dr. Spar said. “But the things that made her unique are now gone, and now she looks like a million other people,” she said. “A million other good-looking people.”